Legal Judgment Prediction (LJP) aims to automatically predict a law case’s judgment results based on the text description of its facts. In practice, the confusing law articles (or charges) problem frequently occurs, reflecting that the law cases applicable to similar articles (or charges) tend to be misjudged. Although some recent works based on prior knowledge solve this issue well, they ignore that confusion also occurs between law articles with a high posterior semantic similarity due to the data imbalance problem instead of only between the prior highly similar ones, which is this work’s further finding. This article proposes an end-to-end model named D-LADAN to solve the above challenges. On the one hand, D-LADAN constructs a graph among law articles based on their text definition and proposes a graph distillation operator (GDO) to distinguish the ones with a high prior semantic similarity. On the other hand, D-LADAN presents a novel momentum-updated memory mechanism to dynamically sense the posterior similarity between law articles (or charges) and a weighted GDO to adaptively capture the distinctions for revising the inductive bias caused by the data imbalance problem. We perform extensive experiments to demonstrate that D-LADAN significantly outperforms state-of-the-art methods in accuracy and robustness.

Graph retrieval aims to find the most similar graphs in a graph database given a query graph, which is a fundamental problem with many real-world applications in chemical engineering, code analysis, etc. To date, existing neural graph retrieval methods generally fall into two categories: Embedding Based Paradigm (Ebp) and Matching Based Paradigm (Mbp). The Ebp models learn an individual vectorial representation for each graph and the retrieval process can be accelerated by pre-computing these representations. The Mbp models learn a neural matching function to compare graphs on a pair-by-pair basis, in which the fine-grained pairwise comparison leads to higher retrieval accuracy but severely degrades retrieval efficiency. In this paper, to combine the advantage of Ebp in retrieval efficiency with that of Mbp in retrieval accuracy, we propose a novel Graph RetrievAl framework via KNowledge Distillation, namely GRAND. The key point is to leverage the idea of knowledge distillation to transfer the fine-grained graph comparison knowledge from an Mbp model to an Ebp model, such that the Ebp model can generate better graph representations and thus yield higher retrieval accuracy. At the same time, we can still pre-compute and index the improved graph representations to retain the retrieval speed of Ebp. Towards this end, we propose to perform knowledge distillation from three perspectives: score, node, and subgraph levels. In addition, we propose to perform mutual two-way knowledge transfer between Mbp and Ebp, such that Mbp and Ebp complement and benefit each other. Extensive experiments on three real-world datasets show that GRAND improves the performance of Ebp by a large margin and the improvement is consistent for different combinations of Ebp and Mbp models. For example, GRAND achieves performance gains of mostly more than 10% and up to 16.88% in terms of Recall@K on different datasets.

Graph Neural Networks (GNNs) have been success-fully applied to a variety of graph analysis tasks. Some recent studies have demonstrated that decoupling neighbor aggregation and feature transformation helps to scale GNNs to large graphs. However, very large graphs, with billions of nodes and millions of features, are still beyond the capacity of most existing GNNs. In addition, when we are only interested in a small number of nodes (called target nodes) in a large graph, it is inefficient to use the existing GNNs to infer the labels of these few target nodes. The reason is that they need to propagate and aggregate either node features or predicted labels over the whole graph, which incurs high additional costs relative to the few target nodes. To solve the above challenges, in this paper we propose a novel scalable and effective GNN framework COSAL. In COSAL, we substitute the expensive aggregation with an efficient proximate node selection mechanism, which picks out the most important$K$nodes for each target node according to the graph topology. We further propose a fine-grained neighbor importance quantification strategy to enhance the expressive power of COSAL. Empirical results demonstrate that our COSAL achieves superior performance in accuracy, training speed, and partial inference efficiency. Remarkably, in terms of node classification accuracy, our model COSAL outperforms baselines by significant margins of 2.22%, 2.23%, and 3.95% on large graph datasets Amazon2M, MAG-Scholar-C, and ogbn-papers100M, respectively.11Code available at https://github.com/joyce-x/COSAL.

Understanding mobile data traffic and forecasting future traffic trend is beneficial to wireless carriers and service providers who need to perform resource allocation and energy saving management. However, predicting wireless traffic accurately at large-scale and fine-granularity is particularly challenging due to the following two factors: the spatial correlations between the network units (i.e., a cell tower or an access point) introduced by user arbitrary movements, and the time-evolving nature of user movements which frequently changes with time. In this paper, we use a time-evolving graph to formulate the time-evolving nature of user movements, and propose a model Graph-based Temporal Convolutional Network (GTCN) to predict the future traffic of each network unit in a wireless network. GTCN can bring significant benefits to two aspects. (1) GTCN can effectively learn intra- and inter-time spatial correlations between network units in a time-evolving graph through a node aggregation method. (2) GTCN can efficiently model the temporal dynamics of the mobile traffic trend from different network units through a temporal convolutional layer. Experimental results on two real-world datasets demonstrate the efficiency and efficacy of our method. Compared with state-of-the-art methods, the improvement of the prediction performance of our GTCN is 3.2 to 10.2 percent for different prediction horizons. GTCN also achieves 8.4× faster on prediction time.